As computers and other electronic devices become more popular, touch-sensing systems are becoming more prevalent as a means for inputting data. For example, touch-sensing systems can be found in automatic teller machines, personal digital assistants, casino game machines, mobile phones, and numerous other applications.
Capacitive touch sensing is a widely used technique in touch screen industries. Capacitive touch sensors are mainly divided in two groups, namely, continuous capacitive sensors and discontinuous (patterned) capacitive sensors. In a continuous capacitive sensor, the sensor includes a sheet of conducting thin film that is electrically excited from four corners of the touch screen. The signals induced by a user's touch are transmitted from the corners to a controller, where they are decoded and translated into coordinates. In a typical patterned capacitive touch screen, the sensor may include one or more series of parallel conductive bars that are driven from one or both ends with an excitation signal from a controller. The signals induced by a user's touch may be transmitted to the controller with the same lead lines that excite the sensor bars. These signals may then be decoded in the controller and the touch coordinates may be reported to a computer.
Touch sensors utilizing more than one patterned sensing layer are often used to determine the coordinates of a touch with high accuracy, provided that the sensing layers have a suitable pattern geometry. One example of a touch screen assembly 10 that includes two patterned conductive layers 12 and 14 is shown in FIG. 1A and FIG. 1B. The patterned conductive layers 12 and 14 may be made from a transparent conductive material, such as indium tin oxide (ITO), and each layer is generally disposed on a transparent substrate (not shown). Each row of conducting elements of each of the sensor layers 12 and 14 includes a series of diamond-shaped electrodes that are connected to each other with short strips of relatively narrow rectangles. A dielectric layer 16 separates the two conductive layers 12 and 14, and serves to prevent them from coming into direct contact with each other. As an example, the dielectric layer 16 may include an adhesive manufactured from any non-conductive, transparent material.
As shown, the end of each row of the two patterned conductive layers 12 and 14 is coupled to one of a set of lead lines 18 that are in turn coupled to a controller 20. The controller 20 may include circuitry for providing excitation currents to the capacitive sensors 12 and 14 and for detecting signals generated by the sensors. Further, the controller 20 may include logic for processing the signals and conveying touch information to another part of an electronic device, such as a processor.
It is against this background that the systems and methods for providing a diamond pattern on a single layer described herein have been invented.